1. Field of the Invention
In certain cases of mechanical conveyors, particularly accelerated transporters, elements are required, particularly for the handrails, that bend in one direction only, at least in certain zones.
2. Prior Art
The prior art consisted in using chains fitted with locks which oppose the bending. The current state of the art is represented by French patent Nos. 2 274 523 and 2 431 075.
The handrail which is the object of these patents is intended for an accelerated transporter made up of handles linked together in twos by a flexible link. Each handle must be synchronous with the corresponding point of the moving floor, and consequently, the handles must separate from each other in acceleration zones, come closer together in deceleration zones and remain equidistant in constant speed zones. This result is obtained by mounting each handle on a small carriage. Two successive carriages are connected by a flexible link which can bend in only one direction and which provides a hand rest area between two handles. The flexible link element is folded, at right angles to the handle, around a pulley and is secured to a tightening carriage or runner whose track can come closer to or move away from that of the carriage to which the handle is fitted, thus making it possible to ensure the change in speed.
According to these patents, the flexible element is made up of a chain furnished with blocks whose complex shape is designed so that the link element, working as a simply supported beam, i.e., subject to a bending moment and a shearing force, does not deform when brought under load; the flexible element between two handrail handles may itself be used as a handrail in the event of "jostling," for example. The main drawback of this system is its complexity, which generates a relatively high cost.
In the device according to the invention, the flexible element is made up of a continuous flexible link of constant cross-section, such as a belt, cable, or set of belts or cables, which have the characteristic, unlike chains, of offering resistance to the shearing forces, and which are associated with compression blocks of simple form which fit into each other. The application of such a device to a handrail will now be described below by way of example. Similar devices could, however, be used in other conveyor elements for people or goods.